- Enthalpy of atomization
The enthalpy of atomization (also standard enthalpy of atomisation - UK spelling) is the
enthalpychange that accompanies the total separation of all atoms in a chemical substance (either a chemical elementor a chemical compound). This is often represented by the symbol ΔHat O. The associated standard enthalpyis known as the Standard enthalpy of atomization, Δ"H"at O/(kJ·mol-1), at 298 K and 1 atmosphere of pressure, or 100 kPa (kilopascals.)
The enthalpy of atomization of gaseous H2O is, for example, the sum of the HO—H and H—O bond dissociation enthalpies. The enthalpy of atomization of an elemental solid is exactly the same as the
enthalpy of sublimationfor any elemental solid that becomes a monatomicgas upon evaporation.
There is a difference between a solid converting to a gas, and a diatomic gaseous element converting to gaseous atoms. The standard enthalpy is purely based on the production of one mole of gaseous atoms.
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